Apparatus and method for contacting of test objects

ABSTRACT

The invention relates to methods for positioning of a substrate  140  and contacting of the test object  301  for testing with a test apparatus with an optical axis and corresponding devices. Thereby, the substrate is put on the holder  130 . The substrate is positioned relative to the optical axis. A contact unit  150  is also positioned relative to the optical axis, whereby the contact unit is positioned independent of the positioning activity of the substrate. Thereby, a flexible contacting of test objects on the substrate can be realized.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of German patent applicationserial number 102 53 717.8 filed on Nov. 18, 2002.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to the testing of large areas. Thereby,particularly tests with a corpuscular beam are used as a testing method.In particular, the present invention relates to the contacting of testobjects. Specifically, the present invention relates to a method forpositioning and contacting a substrate, a method for the testing of asubstrate, and an apparatus for contacting at least one test object forthe test and to a test system.

[0004] With increasing demand on display elements without picture tubes,the standards for liquid crystal displays (LCD) and other displayelements, in which control elements, for example thin film transistors(TFT), are used increase. These display elements have pixels arranged ina matrix.

[0005] Yet, also in other fields an increasing amount of elements has tobe tested. This can be, for example, microelectronic and/ormicromechanic elements. These elements are for example thin filmtransistors, connection networks of a chip, transistors, electronemitters of an emitter array, the electrodes for pixels of a display,micromechanic mirrors of an array and other elements, which distinguishthemselves in particular by being present as a plurality of elements(100,000 a to several 1,000,000), whereby each element is electricallycontrollable.

[0006] In order to obtain, for example, a good image quality of adisplay element, only a few of the several million pixels are allowed tobe defective. For guaranteeing a cost efficient production it istherefore important, most notably for the display elements continuouslyincreasing in size, to provide high-capacity in situ test methods. Sucha test method is for example disclosed in document EP 523594. Withinthis test method, the individual pixels are tested with a corpuscularbeam. The corpuscular beam can either be used for detecting chargesapplied via a supply line and/or applying charges on a pixel electrode.

[0007] For such test methods contact units are employed, which, on theone hand, allow for a signal transfer to external devices and, on theother hand, admit a scanning with an electron beam. Thereby, accordingto the state of the art, different solutions exist.

[0008] If displays are tested, it is possible to arrange a frame aroundthe area of the display which provides electrical contacts to thedisplay. On one substrate there are generally several displays arranged.Because in view of the limited measurement range of an electron beamsystem only one display each can be tested, for the test of a furtherdisplay that contact units is lifted, the substrate is displaced and thecontact unit is set on the next display. However, using such anarrangement, only displays can be tested whose entire surface can bereached by the scanning of the corpuscular beam.

[0009] Further, there are contact frames that contact all displays of aglass substrate at the same time. Such a contact frame is displaced witha substrate, if other displays are to be tested.

[0010] A disadvantage of such contact frames for the entire substrate isthe necessity to exchange the entire contact frame in the event ofvarying display sizes. For this reason the system must be vented in thecase of varying batches, which reduces the productivity. Further, it isnecessary to store the contact frames for the varying display types anddisplay sizes in order to be applied when demanded.

[0011] The object of the invention is to at least partly solve theproblems of the state of the art. Particularly, the possibility shouldbe given to test during a test different test objects with differentdimensions of test objects with one apparatus.

[0012] Thereby, test objects in the context of the present invention arefor example displays, a group of displays, arrays of othermicroelectronic or micromechanic elements, as well as individualcircuits, which are for example tested on short-circuits and missingcontacts between areas of the circuit.

SUMMARY OF THE INVENTION

[0013] The above-mentioned problems of the state of the art are at leastpartly solved by the inventive apparatuses according to claims 17, 19,21, 35, 40 and 42, as well as the inventive method according to claims1, 6 and 36.

[0014] Preferred embodiments and specific aspects of the invention areevident from the dependent claims.

[0015] According to one aspect, the object of the present invention issolved by a method for positioning of a contact unit during testing witha test apparatus which has an optical axis. Therefore, a substratehaving several test objects is positioned on a sample support, that is,a substrate holder. The substrate is displaced relative to the opticalaxis, so that an area of the test object lies in the measurement rangeof the test apparatus. A contact unit for contacting the test objects ispositioned, whereby the positioning of the contact unit is at leastpartially not coupled to the positioning of the substrate. Thepositioning of the contact unit is suitable for bringing the contactunit in contact with a contact arrangement or several contactarrangements of the test object.

[0016] The object is further solved according to a further aspect of theinvention by a method for testing a substrate with several test objectswith a test apparatus. The substrate is placed on a sample support. Acontact arrangement of a first test object of the test objects on thesubstrate is contacted with a contact unit. The holder and thereby thesubstrate is positioned in order that a first area of the first testobject can be measured in the test range of the test apparatus.Thereupon, the first area of the first test object is tested. The holderand thereby the substrate are newly positioned in order to test at leasta further area of the test object in the test range of the testapparatus. The contact unit is also positioned so that the positionrelative to the substrate is essentially not changed. The at leastfurther area of the test object is tested. The substrate is again newlypositioned in order to test an area of a second test object. The contactunit is displaced relative to the substrate for the test of the area ofthe second test object.

[0017] Contacting of differently formed test objects is possible withthe above described aspects of the present invention without thenecessity of an exchange of the contact unit. Further, it is possible totest test objects with the test apparatus, the size of which exceeds thetest range of the test apparatus. In this context, the components forgenerating the measurement signals are understood as the test apparatus.These are: a source for the generation of a primary corpuscular beam,beam shaping- and beam-deflection components for guiding the beam on asurface, which is used for obtaining the measurement signal, componentsfor guiding and/or imaging of the measurement signal on a detectionunit, and the detecting unit.

[0018] Independent of the fact when comparing to the state of the artthe exchange of the contact unit should be avoided, however, andoccasional exchange can be beneficial for maintenance or the like. Thecontact unit is typically an exchangeable unit.

[0019] Within the scope of the above-mentioned aspects, it isparticularly preferred if the positioning of the contact unit takesplace with a drive assigned to the contact unit. Thereby, the contactunit can fast and flexibly be moved from one position to the nextposition. This increases the test velocity of the entire substrate and,thereby, the throughput of the test system.

[0020] According to a further aspect, the inventive object is solved byan apparatus for contacting, which is used for test system. This systemincludes a sample support with a positioning unit. The positioning unithas, in both directions perpendicular to the optical axis of the testapparatus, a displacement range. The contact unit also has, in bothdirections perpendicular to the optical axis of the test apparatus, adisplacement range. Thereby, at least one displacement range of thecontact unit is smaller than the corresponding displacement range of thesample support.

[0021] According to an aspect of the invention an apparatus forcontacting is disclosed. This includes a holder for a substrate and acorresponding displacing unit. Further, there exists an alsodisplaceable contact unit, which has at least in one direction,perpendicular to an optical axis of a corpuscular beam tester, a smallerdimension than the dimension of the holder in this direction.

[0022] A principal aspect of the invention is an apparatus forcontacting. This includes a holder for a substrate and a correspondingdisplacement unit. Further, there exists an also displaceable contactunit, which has at least in one direction perpendicular to an opticalaxis of a corpuscular beam tester at maximum half of the dimension ofthe holder in this direction.

[0023] Thereby, the holder can be a substrate table on arrangement ofrollers on which the substrate is shelved. The holder is a substrateholding unit. That is, the substrate lies on the holder or the holdersupports the substrate respectively.

[0024] According to a further aspect of the invention, an apparatus forcontacting is disclosed. This includes the holder for a substrate and acorresponding displacing unit. Further, there exists an alsodisplaceable contact unit which is at least in one direction,perpendicular to the optical axis of a corpuscular beam tester, smallerthan the substrate or has at maximum half of the dimension of thesubstrate in this direction.

[0025] Apparatuses, which can be improved by the present invention,often have a holder larger than the substrate. In the event that thesubstrate should be large than the holder, the above-mentioned relativesizes between the contact unit and the holder refer at least to thesubstrate to be inspected. This means, that the relative sizes are givenfor the contact unit relative to the substrate.

[0026] Thereby, it is particularly preferred if the contact unit has, inboth directions perpendicular to the optical axis of a corpuscular beamtester, at maximum half of the dimension of the holder in thisdirection.

[0027] The present invention can also be phrased as follows. Accordingto one aspect of the invention, the object is solved by an apparatus forcontacting within a test system. The test system includes a holder,which is displaceable relative to the optical axis of the testapparatus, and a contact unit, which is also displaceable relative tothe optical axis. The contact unit is during the test of the substratealso displaceable with respect to the substrate.

[0028] With regard to this aspect, it is preferred if the contact unitis displaceable during the testing of the test objects of a substrate byat least 10 cm, especially preferred by at least 25 cm.

[0029] According to a further aspect, the inventive object is solved bya test system. The test system includes a corpuscular beam column, atest chamber, and an apparatus for contacting of at least one testobject of a substrate according to one of the above-mentioned aspects.

[0030] Thereby, it is preferred if the test chamber can be evacuated.Further, it is preferred if the corpuscular beam column is an electronbeam column, whereby particularly an emitter, deflection units and beamshaping optics are included in the column.

[0031] According to the present invention, the corpuscular beam can beformed by photons, that is a light optical test of the elements of thetest objects on the substrate is conducted.

[0032] Further, in order to save the space required for a displacementof the glass substrate, it is possible not to move the glass substrateand a contact unit relative to the optical axis of the test apparatus,but to keep the glass substrate rested. In such a case, on the one hand,the optical axis of the test apparatus is moved relative to the glasssubstrate. Further, on the other hand, the contact unit is movedrelative to the glass substrate and the contact unit and the opticalaxis of the test apparatus are moved relative to each other.

[0033] The invention also relates to apparatuses with features that arenecessary to conduct the described methods. Further, the inventionrelates to methods that are characterized by the usage of the describedapparatuses.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Embodiments of the invention are described in the drawings andare exemplarily described in more detail in the following.

[0035] Therein:

[0036]FIG. 1 shows a schematic side view of a test system according tothe present invention;

[0037]FIG. 2 shows a schematic view of two embodiments of a contactassembly on a test object preferred according to the present invention;

[0038]FIGS. 3a to 3 d show schematic top views on a substrate withseveral test objects on a holder and the usage of the contact unitaccording to the present invention;

[0039]FIG. 4 shows a schematic view of the usage of the subjectinvention and the advantages;

[0040]FIG. 5 shows a schematic top view of an embodiment according tothe present invention;

[0041]FIG. 6 shows a schematic top view of a further embodimentaccording to the present invention;

[0042]FIG. 7 shows a schematic side view of an embodiment the inventionis based upon;

[0043] FIGS. 8 to 8 c show schematic views variations of furtherembodiments the invention is based upon;

[0044]FIG. 9 shows a schematic view of an example for illustration ofthe used terms;

[0045]FIG. 10 shows a schematic side view of a further test system; and

[0046]FIGS. 11a to 11 d show schematic top views on a substrate withseveral test objects on a holder and the usage of the contact unitaccording to a further aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0047] The present invention can be used for a variety of test methods.For simplicity, the present invention is in the following at firstdescribed by the testing of displays with an electron beam.

[0048] Thereby, at first, the terms used are illustrated with respect toFIG. 9. FIG. 9 shows a top view onto a glass substrate 140 on a samplesupport 130. On the substrate, the six displays 301 are fabricated.Thereby, as an example, the displays are distributed on the glasssubstrate with uniform distances. The glass substrate is provided in atest chamber (see FIG. 1). This means that during an inspection of thedisplays, the electron beam column is located above the glass substratethat is shown in FIG. 9. For clarification, the optical axis 102 of theelectron beam is shown in FIG. 9.

[0049] For the testing of a display, the electron beam is scanned overthe glass substrate with deflectors. Thereby, an area 302 is detected bythe electron beam. This area is, in the following, denoted as test range302 and is indicated gray. Thereby, the test range 302 is the area whichcan maximally or in a reasonable manner be tested by the electron beam.This means that in an area of the sample external to the test range 302,no measurement results can be gathered by the test method. The testrange is, as a result, independent of the substrate to be inspected. Itis rather a characteristic of the test apparatus, thus, the electronbeam test device.

[0050]FIG. 9 shows the display 301 that is larger than the test range302 of the test apparatus. Thus, the display can not be tested by thetest apparatus without displacing the glass substrate 140 with thedisplays relative to the optical axis 102. For this reason, the displaysin FIG. 9 have to be divided into several areas, which are tested oneafter the other. These areas are the first area 303 and the second area304. Consequently, during the test of the first display (top left), theglass substrate is displaced in order to position the first area 303within the test range 302 of the test apparatus. Thereafter, the glasssubstrate is again displaced with respect to the optical axis 102 inorder to position the second area 304 within the test range of the testapparatus. A displacement relative to the optical axis 102 is therebysimilar to a displacement relative to the test range 302.

[0051] Generally, displays have to be electrically contacted for testmethods in order to test the functionality of the displays. Therefore, acontact unit 150 is placed on the glass substrate. This contact unitprovides electrical contacts to the displays. Thereby, the displays canbe electrically connected to external devices necessary for the test.

[0052] With reference to FIG. 7 and the FIGS. 8a to 8 c, next, the ideasforming the basis of the invention will be described.

[0053] The assembly 700 in FIG. 7 shows a top view of the glasssubstrate 140. There are a several displays 708 to be tested or circuitsfor displays 708 to be tested on the glass substrate. The assembly 700is inserted in a test system for testing. In the test apparatus, thedisplays are inspected with an electron beam. Thereby, the electron beamis scanned over an area of the substrate. Thereby, measurements resultscan only be gathered within the test range 704 of the test apparatus.

[0054] The entire glass substrate is too large to be tested by anelectron beam without displacement. For conducting a measurement of anarea of a display, the area being within the test range, the display 708is contacted with a contact unit 706 via the contact arrangement 702.Thereby, measurement signals as well as other externally provided testsignals can be transmitted between the display under test and ameasurement electronic.

[0055] Within FIG. 7, the displays have a dimension that is smaller orequal to the test range 704. Firstly, the glass substrate is positionedso that a first display is provided within the area 704 of the testapparatus, which can be used for the measurement with the electron beam.For the assembly 700, a contact unit 706 is put on the glass substrate.Thereby, contact pins of the contact unit are contacted with contactassembly 702 designed therefore, which are provided on the glasssubstrate for contacting each displays 708. External signals can beprovided to the display via these contacts. If required for themeasurement method, signals of the displays can also be measured viathese contacts.

[0056] For the testing of all displays on the glass substrate 140,firstly, a first display is contacted. Afterwards, this display isinspected with the electron beam test method. Then, the contact unit 706is lifted and the glass substrate 140 is displaced. Thereby, a furtherdisplay is positioned in the test range of the test apparatus. Thecontact unit 706 is contacted with the further display in order toinspect this display. In doing so, all displays on the substrate areinspected. However, with this embodiment, only displays can be inspectedwhose dimensions are within the range that can be inspected with theelectron beam.

[0057]FIGS. 8a to 8 c show a further assembly 800 or 800 b,respectively. All displays 808 on the glass substrate 140 are contactedwith the contact unit 806 or 806 b, respectively, for the assemblies 800and 800 b. If the glass substrate is displaced during the testing ofdifferent areas of the glass substrate 140, the contact unit that restson the glass substrate is carried along.

[0058]FIG. 8a shows the glass substrate 140. The contact unit 806contacts all displays 108 for realization of the test. In order to beable to provide all displays 808 with signals or being able to receivesignals from all displays, respectively, the contact unit 806 has a bondbridge 810.

[0059] The assembly 800 b in FIG. 8b is comparable to assembly 800. Thecontact unit 806 b simply includes a grid-like bond bridge 810 b.

[0060]FIG. 8c again shows the assembly 800. Contrary to FIG. 8a, inhere, the displays 808 b have different dimensions.

[0061] As realized by comparing FIG. 8a with FIG. 8c, the bridge 810covers a part of the display 808 b to be tested; therefore, a reasonabletest is not possible. Thus, it is required for the inspection of thedisplays 808 b to choose a different shape for the contact unit. Inorder to realize this in practice, the test apparatus is vented, thecontact unit 806 or 806 b, respectively, is removed, a contact unitsuitable for the new displays 808 b is inserted in the system, and thesystem is newly evacuated.

[0062] Since the venting and the evacuating involves large disadvantagesin the course of production, it is desirable to reduce such problemswith the present invention.

[0063] In the following, embodiments and preferred aspects of thepresent invention are illustrated with respect to FIGS. 1 to 6.

[0064]FIG. 1 shows a test system 100. The test system inspects testobjects, for example displays provided on a glass substrate 140 oranother substrate, by means of corpuscular beams. The test systemincludes, as one part, a test apparatus for example in terms of thecolumn 104. Within the column the corpuscular beam is generated in theemitter 10.

[0065] With regard to this invention, corpuscular beam is to beunderstood as a beam of charged particles (particle beam), such as forexample an electron or ion-beam, or a laser beam. This means that theterm corpuscular beam is to be understood as a laser beam, in which thecorpuscles or photons, as well as a particle beam, in which thecorpuscles are ions, atoms, electrons or other particles. As an example,in the following, it is referred to an electron beam.

[0066] Further, FIG. 1 shows apertures 12, deflectors 14 and lens 16.These serve, inter alia, for imaging of the electron beam along theoptical axis 102. The displacing units 132 and 134 are provided in thetest chamber 108. The sample support 130 can be displaced in x-directionand y-direction with the displacing units. In FIG. 1, this is realizedby two displacing units that are displaceable with respect to eachother. Thus, on displacement of the displacing unit 134 in x-direction,the displacing unit 132 as well as the holder with the substrate isdisplaced in x-direction. Independent thereof, the displacing unit 132is controlled for a displacement of the sample support 130 with theglass substrate 140 in y-direction. Thereby, the sample support with thesubstrate can be moved in the x-y-plane.

[0067] The test chamber can be evacuated through the vacuum flange 112.Holder or sample support 130, respectively, are moved with thedisplacing units. The glass substrate 140 is provided on the holderduring the measurement. Further, the contact unit 150 with a drive 152is provided within the test chamber 108. During the measurement, adisplay on the substrate is contacted with the contact unit in order torealize an electrical contact of the display with the test system.

[0068] The drive 152 serves for an independent moving of the contactunit relative to the optical axis 102 of the test apparatus and relativeto the sample support 130. A signal connection of the contact unit 150takes place with the contact connection 154. Further, within FIG. 1, thecontrol and operation units 135, 153, 160, 162, and 164 are shown, whichare illustrated in more detail with respect to the usage of the testsystem 100.

[0069] Referring to FIG. 1, in the following, the functionality of thetest system is described. The electron beam generated by emitter 10 isguided via elements like apertures 12, deflectors 14 for beampositioning and for scanning, as well as lenses 16 in the test chamber108. Additionally, the beam is formed by the optical elements.

[0070] For the test methods, the electron beam is directed on an elementof the display on the substrate. Thereby, a charging of areas of theelement to be tested can be achieved. Further, it is also possible tomeasure emitted secondary particles with a detector (not shown). By themeasurement of the secondary electrons, it is possible to measure thepotential distributions on the displays; as well as, topologies ormaterial compositions can be determined with other detection methods.

[0071] An evacuation of the column 104 can be conducted through thevacuum flange 106. Further connections (not shown) serve for connectionwith external control devices. These control devices can be computers,control units, and central control systems with a user interface.

[0072] A displacing unit (132+134) is provided in the test chamber 108.This is for example formed by two linear displacing units. Thereby, adisplacement in x-direction is conducted with the displacing unit 134and a displacement in y-direction is conducted with displacement unit132. The displacing units are connected with the control unit 135. Thecontrol unit controls the positioning of the holder 130 (sample support)in the x-y-plane.

[0073] The holder 130 for holding of the substrate 140, that is thesample support, is moved relative to the optical axis 102 of theelectron beam column with the displacing unit (132+134).

[0074] During the test of displays on the substrate, the displays eitherhave to be fed with external signals, or signals, which are generatedwithin the displays, have to be measured and applied to an evaluationunit. Therefore, the displays are electrically contacted. For this, thecontact unit 150 is used. The contact unit provides with the contactpins an electric contact to the contact assembly 200 (see FIG. 2). Thecontact assembly 200 can either serve for contacting of one display orfor contacting of several displays.

[0075]FIG. 2 shows two examples for a contact assembly 200. The contactassemblies include individual contact pads 212. These are arranged on anarea 210. The distances between the contact pads are denoted 220 and 222within FIG. 2.

[0076] The contact assembly 200 or several of the contact assemblies 200are provided together with the display on the substrate. The controllines or measurement lines of the displays are connected via feed lineswith the pads 212 of the contact assembly. The pads have a standardizeddistance in x-direction 220 and a standardized distance in direction222. Through this, an automated contacting is possible. The twoexemplarily shown embodiments differ with respect to the number andarrangement of the contact pads. For contacting of the contact unit witha display, contact pins of the contact unit are guided on the contactpads of the contact assembly 200. Thereby, the individual contact pinsfor a standardized contact assembly have preferably a fixed distancewith respect to each other.

[0077] The contact pins of the contact unit are not moved relative toeach other for contacting of the contact paths of the contact assembly.This applies to essentially all contact pins relative to each other.Here, essentially is to be understood as at least 90% of the contactpins, preferably as 100% of the contact pins.

[0078] Independent of exemplarily embodiments, it is an advantage forthe present invention if the contact areas 200 have an assembly which isidentical for different types of displays. By means of the presentinvention, it is possible to test a variety of different displays withone contact unit. Therefore, however, it is preferred if the contactassembly is standardized in order to reduce or avoid the necessity of anadaptation to the geometrical arrangement of the pads 212. Thus, withoutthe existence of a limitation with respect to the flexibility of thetest system, the contact pins of the contact unit also can have a fixedgeometric arrangement with respect to each other.

[0079] For contacting of the contact unit 150 (see FIG. 1) with thecontact assembly, the contact unit is moved from above onto the displayor the substrate, respectively. In order to ease an adjustment of thecontact unit with respect to the contact pads 212, it is advantageous ifthe contact unit and the substrate are displaceable in x-direction andy-direction by a contact displacement range. Thereby, in each direction,the contact displacement range has the dimension of the distances of thecontact pads 220 or 222, respectively.

[0080] In FIG. 1, the signal transmittal takes place via the contactunit 150 to a display on a substrate 140 via the contact connection 154.The signals are made available via a control unit 162. With such a unit,if need be, also signals of the display can be measured, which aretransmitted with the contact unit.

[0081] In order to allow a testing with the electron beam, it is furtherpossible to generate a vacuum in the test chamber 108. The vacuum flange112 serves therefore. An evacuation of the test chamber is conductedduring the test to a pressure of maximum 1*10-2 mbar, preferably to apressure of maximum 1*10-4 mbar. Furthermore, other flanges (not shown)exist, which allow the connection to control units, control computers164, external communication means, or the like.

[0082] In the following, the test method with the test system 100 isdescribed by means of an electron beam, without limiting the inventionthereto. A possible test method is to charge electrodes of, for example,pixels of a display on a potential via input leads. This potential orthe variation thereof in time, respectively, can be measured with acorpuscular beam. Thereby, it is possible to detect defects such asshort-circuits or missing contacts, as well as to determine parasiticelements and the amplitude thereof.

[0083] In another method, the electrodes of the pixels are charged via acorpuscular beam and the resulting potentials are also measured with acorpuscular beam. The starting conditions and boundary conditions arearranged with the control of the input leads.

[0084] In the further method, the electrodes of the pixels are chargedvia a corpuscular beam and the resulting current in the input leads ismeasured.

[0085] In the following, the principle of the present invention isillustrated exemplarily with regard to FIGS. 3a and 3 b.

[0086] Assembly 300 in FIGS. 3a and 3 b show, in a top view, a glasssubstrate 140, which is located on a sample support 130. Displays 301 orcircuits of a display 301, which are to be tested in the apparatus, areprovided on the glass substrate. FIGS. 3a and 3 b show the sameassembly, whereby the glass substrate is moved relative to the indicatedguide 350.

[0087] Further, FIGS. 3a and 3 b show a contact unit 150. The contactunit has the shape of a frame. The frame has a size sufficient not tocover an area of the display to be tested. The test range 302, which canbe tested with the electron beam, is indicated gray within FIG. 3. Thetest range gives the area which can be detected with the test apparatus.External of the test range no measurements can be conducted with theelectron beam. Within the test range, the electron beam measures bydeflecting the electron beam with a scanning unit. Thereby, the electronbeam is deflected in x-direction and y-direction with a scanning unit,so that the test range 302 can be recorded sequentially with theelectron beam. Alternatively, it is possible to deflect the electronbeam only in one direction and to realize an expansion of the test rangein another direction by moving of the substrate.

[0088] The displays 301 to be tested are larger than the test range 302of the test apparatus. Thus, several areas of the display have to beinspected apart from each other. For this reason, the displays arepartitioned in a first area 303 and a second area 304. In the embodimentshown in FIG. 3, the areas 303 and 304 correspond to a half of adisplay. Further, the size of the test range is similar to the size ofthe first area 303 and the second area 304 of the displays 301. Thisaccordance is accidental and not relevant for the invention.

[0089] During the method according to the present invention, a glasssubstrate 140 as well as the contact unit 150 are displaced. Thesedisplacements, which are conducted within the method described withrespect to FIG. 3, are indicated by arrows. Within FIG. 3, thedisplacement of the sample support 130 with the substrate 140 innegative x-direction is denoted by arrow 312. The analogous displacementof the contact unit in negative x-direction is denoted by the arrow 310.A further displacement (transit from FIG. 3b to FIG. 3c) is denoted by314.

[0090] For the inspection of the display, a contacting of the contactassemblies with the contact unit 350 is necessary. Within FIG. 3, thecontact unit has the shape of a frame. Advantageously, this frame issufficiently large in order not to cover any area of the display 301.

[0091] During the test method, firstly the first area 303 of a display,which is positioned within the test range 302, is tested. Thiscorresponds to a relative arrangement of the glass substrate 140 and thecontact unit 150 to the optical axis 102 as indicated in FIG. 3a. Theoptical axis 102 and the test range 302 do not move relative to eachother (during any of the method steps). The test range 302 results froma deflection of the electron beam from the optical axis 102. Thereby,the size of the test range 302 is for example limited by a maximumdeflection of the electron beam from the optical axis 102.

[0092] After the testing of the area 303 of the display, the substrateis displaced by the distance 312 in negative x-direction. As can be seenin FIG. 3b, thereby, the second area 304 of the display 301 ispositioned in the test range 302 of the test apparatus. Thus, the secondarea 304 of the display can be tested. A contacting by the contact unitis also necessary for the test of the second area 304 of the displays301. Therefore, the contact unit is also displaced. The displacement 310in negative x-direction is thereby essentially identical to thedisplacement 312 of the substrate. Thereby, the contact unit 150 iscarried along with the substrate (displacement 312) so that a contactingis present during the entire time.

[0093] After the displacement of the glass substrate 140 and the contactunit 150, the situation shown in FIG. 3b is given. The second area 304of the first display can now be tested. For testing all displays 301 onthe substrate 140, the substrate 140 has to be displaced again relativeto the optical axis 301 (and thereby also to the test range 302). Thisdisplacement of the substrate is indicated by arrow 314. Afterwards, thesituation shown in FIG. 3c is given.

[0094] The transit from FIG. 3b to FIG. 3c clarifies the steps for thetesting of a further display. Firstly, the contact unit 150 is lifted.The substrate is displaced relative to the contact unit (see arrow 314),whereby the contact unit is positioned above a further display.Afterwards, the contact unit is contacted with the further display. Thedisplacement of the substrate relative to the test range 302 or to anoptical axis of an electron beam, respectively, is, within FIG. 3,additionally illustrated by the guide 350.

[0095] For the second display to be tested in FIG. 3b a test method isapplied, which is conducted analogously to the method described in FIG.3a. At first, a first area 303 of the second display 301 is positionedin the test range 302 of the electron beam test apparatus. One orseveral test methods can be applied to the first area 303 of the seconddisplays 301 by means of the contact of the display with the contactunit 150. Afterwards, analogously to the displacements 310 and 312 (FIG.3a to FIG. 3b), the glass substrate 140 as well as the contact unit 150are displaced also for the second display. These two displacementsresult in the situation shown in FIG. 3d. Thereby, the second area 304of the second display can also be tested using the contact unit 150.

[0096] In order to swap for the test of a display 301 from the firstarea 303 to the second area 304, as described above, the glass substratehas been moved in negative x-direction (see 312) as well as the contactunit has been moved essentially by the same amount in the samedirection.

[0097] There are several possibilities to realize this paralleldisplacement. On the one hand, the contact unit 150 can be carried alongwith the substrate 140. Carried along in this context means that duringthe contacting of the contact unit with the contact assembly of thedisplay 301, also a mechanical contact is established so that, duringthe movement 312 of the substrate, the contact unit is moved by thesubstrate.

[0098] On the other hand, it is possible that the contact unit 150 hasits own drive 152 (see FIG. 1). Thereby, the contact unit can bepositioned autonomously and independently from the substrate. Thus, itis possible that the contact unit 150 follows the movement of thesubstrate.

[0099] Thereby, the substrate 140 and the contacting can be displacedsynchronously, whereby the synchronization unit 160 is used. Adisplacement of the substrate and the contact unit can thus be realizedwithout disconnecting the electrical contact. By means of the own driveof the contact unit, it is also possible to lift the contact unit and todisplace the contact unit detached from the substrate. In this case, itis newly put onto.

[0100] The embodiment described with respect to FIGS. 3a and 3 b, cangenerally be described as the following inventive aspect.

[0101] The above described inventive method and inventive contact unitwas exemplarily described for displays. The method can also be used fortesting of other test objects. Test objects are to be understood withinthe present invention as for example displays, a group of displays,arrays of other microelectronic or micromechanic elements, as well asindividual circuits that are for example tested with regard toshort-circuits or missing contacts between areas of the circuits.

[0102] The present invention allows the test of test objects havingdifferent sizes with the same contact unit. Thereby, the contact unitcan be positioned relative to the optical axis of a test apparatus andrelative to a test object to be tested.

[0103] The test objects 301 have been described with regard to theembodiment of FIGS. 3a and 3 b as a display 301. However, a test objectcan also be a group of displays and other devices that are tested withcomparable methods.

[0104] The present invention is particularly advantageous for testmethods in which only a limited area of the test object can be testedwithout movement of the substrate with the test objects. This meanswithin the example of FIG. 3 that the area of the test object (display301) to be tested is larger than the test range 302.

[0105] Nowadays, an area of above 20 cm×20 cm can be tested by testingof displays with corpuscular beams. Nowadays, flat-panel displaysalready have a size of the image diagonal of 17″, 19″ or larger. Duringproduction, several flat-panel displays are fabricated on one glasssubstrate. The dimensions of the glass substrate in one or in bothdirections can be about 1500 mm or larger.

[0106] According to this, the inventive methods or a test systems arepreferably used for test ranges of above 50 mm×50 mm, especiallypreferably for test ranges of above 200 mm×200 mm. This holdsindependently of specific embodiments.

[0107] Further, independent of specific embodiments, it is preferred ifthe test systems and methods according to the present invention inspecttest objects with a dimension in one or both directions of at least 200mm, especially preferred of at least 400 mm.

[0108] Further, it is generally preferred for the present invention ifit is applied for test methods and apparatuses for substrates with adimension in one or in both directions of at least 700 mm, especiallypreferred of at least 1200 mm.

[0109] Substrate displacements and contact unit displacements that canbe realized are preferably at least 50 mm, especially preferably atleast 300 mm. In particular, it is preferred if the range of thesubstrate displacement is larger than the range of the contact unitdisplacement and is at least 700 mm. This holds for all embodimentswhich are mentioned exemplarily for clarification of the presentinvention.

[0110] Independent of specific embodiments, it is preferred if thecontact unit 150 has its own drive 152 (see FIG. 1) and, thereby, thecontact unit can be positioned autonomously and independently from thesubstrate. In this case it is possible that the contact unit 150 tracksthe movement of the substrate.

[0111] The tracking can be realized by synchronizing the movement of thesubstrate and the contact unit. A displacement of the substrate and thecontact unit can thus take place without disconnecting the electricalcontact. By means of the drive of the contact unit, it is also possibleto lift the contact unit and to move it detached from the substrate.

[0112] Compared to the principle described with respect to FIG. 7, thepresent invention has the advantage that test objects 301 can bemeasured, which are larger than the test range 302 that is predeterminedby the test method. This is achieved by the displaceability of thecontact unit.

[0113] Advantages as compared to the principle described with respect toFIGS. 8a to 8 c, are illustrated in the following with respect to FIG.4.

[0114]FIG. 4 shows a substrate support 130 with the glass substrate 140.Displays 401 are to be tested with the above described method. Displays401 are also too large to lie within the test range 302 of the testapparatus. Thus, displays 401 also have to be partitioned into areas 303a and 304 a, which are tested independently of each other. Accordingly,a first area 303 a and a second area 304 a of a display 401 is marked inFIG. 4. Exemplarily, these areas correspond to a half of a display.

[0115] The contact unit 150 in FIG. 4 has the same size as the contactunit 150 in FIG. 3. Due to the different dimensions of the displays 401as compared to the displays 301, the contact unit covers parts of adisplay 401 in FIG. 4. The contact unit 806 as shown in FIG. 8 cannot beadapted to the different dimensions. Thus, for a contact unit accordingto FIGS. 8a to 8 c, it is necessary to use different types of contactunits 806 (see FIG. 8) for different types of test objects.

[0116] However, the inventive contact unit 150 can be placed atdifferent locations of the substrate. Consequently, for the presentinvention, the inspection procedure is not disturbed by the covering ofa display, which is not tested at the time being (in FIG. 4, top middledisplay).

[0117] The display type 401 also has a size that is larger than the testrange 302. Thus, analogously to the steps described with respect to FIG.3, the contact unit 150 is here also displaced with the substrate 140 ina manner, that the contacting of the display 401 is possible during thetesting of the first area 303 a and the second area 304 a.

[0118] As can be seen in FIG. 4, the contact unit 150 does not have adirect contact at all four sites of the display 401 to the display to bemeasured, respectively. Thus, it is advantageous for the presentinvention if the contact assembly 200 or several of the contactassemblies 200, by means of which the contact between the contact unit150 and the display is established, are arranged, that the contactingalso takes place at varying dimensions of the displays. In FIG. 4, allcontact assemblies 200 are arranged at the top side of the respectivedisplay 401. Therefore, in this case, the contacting of the contact unit150 is independent of the dimensions of the display.

[0119] Thus, contrary to the basic principle shown with respect to FIG.8, the different types of displays can be tested with the presentinvention without exchanging or swapping the contact unit 150.

[0120] The similar is also true for the embodiment shown in FIG. 5.Analogously to the previous figures, the embodiment described in FIG. 4,shows a substrate support 130 with a glass substrate 140. The contactunit in FIG. 5 includes a first part 150 a and a second part 150 b. Theembodiment of the contact unit 150 in FIG. 5 has the same inventivecharacteristics as the contact unit in FIG. 3. That means that thecontact unit in FIG. 5 can also be positioned relative to the opticalaxis of the test apparatus and independent of the positioning of theglass substrate.

[0121] Furthermore, the contact unit 150 in FIG. 5 gives an additionallyimproved flexibility by being able to vary the size of the contact unit150. The modification of the size of the contact unit 150 in FIG. 5 isrealized by a displacement of the two parts 150 a and 150 b, which isindicated by arrow 504.

[0122] Further, FIG. 5 shows a first display type 301 a and a seconddisplay type 301 b. The two display types differ by their dimensions.Arrow 502 symbolizes the difference in size between the displays 301 aand 301 b. As mentioned above, arrow 504 describes a modification of thesize of the contact unit 150. The modification of the size can beadapted to the difference in size of the two display types 301 a and 301b.

[0123] If, within FIG. 5, other displays of the type 301 b are testedinstead of a first display type 301 a, the contact unit can be adaptedto the modified display size or display form. The modification of thesize 502 is compensated by a displacement 504 of the parts 150 a and 150b of the contact unit.

[0124] By this preferred aspect, an even larger flexibility can begenerated. For such an embodiment, an additional positioning unit forthe two parts 150 a and 150 b relative to each other is provided.Alternatively, for both parts 150 a and 150 b of the contact unit 150 aseparate positioning unit can be provided, respectively. Independent ofa modification of the dimension of the contact unit 150 by thedisplacement 504 of the two parts of the contact unit 150, it is herealso preferred (see explanations to FIGS. 2 and 4) if the differenttypes of displays have identical or compatible contact assemblies 200.

[0125] The embodiments described with respect to this invention refer tocontact units that are essentially formed by a rectangular frame orparts of a rectangular frame. This is preferred for the presentinvention since it has the advantage to carry out a contacting of thedisplay from all four sides.

[0126] The present invention is not limited thereto. The inventive ideacan also be realized with a bar shaped, several bar shaped or othercontact units. For example, for the contact assembly 200 in FIG. 4, acontact bar at the top side or at another side of the display issufficient. For a further contacting at a further side face of thedisplay, the contact unit in the form of a corner is sufficient.

[0127] As already mentioned with respect to FIG. 5, in the event thatseveral parts of the contact unit exist, it is preferred if severaldrives for positioning the part of the contact unit exist. Theadditional drives can either be used for the positioning of theindividual parts relative to the optical axis of the test apparatus orfor the positioning relative to each other.

[0128]FIG. 6 shows a further embodiment of the present invention. Again,there is a substrate support 130 with a glass substrate 140. Thedisplays 301 or circuits required for the displays, respectively, arearranged on the glass substrate. The test range 302 predetermined by thetest apparatus is indicated gray in FIG. 6. Further, FIG. 6 shows acontact unit 150. The contact unit 150 covers six displays. Thus, FIG. 6can be interpreted as if a test object consisting of six displays has tobe tested. Consequently, the test object is so large that testing of thetest object cannot be conducted by the test of two areas as in FIG. 3(there: test object=display). In FIG. 6, in fact 12 areas are tested toobtain all test results relevant for the inspection of the entire testobject.

[0129] Therefore, the first test object is partitioned in 12 areas I toXII. Each of these areas has the same size as to test range 302 of thetest apparatus. The accordance of the sizes of the test range 302 andthe areas I to XII is exemplarily and not limiting for the presentinventive idea.

[0130] Further, the following dimensions and displacement ranges areindicated in FIG. 6, in order to refer to respective displacementsduring the description of the test method. The dimensions of thesubstrate support are denoted in x-direction with 602 and in y-directionwith 604. Arrow 610 symbolizes the displacement range of the substratein x-direction. Arrow 614 symbolizes the displacement range of thesubstrate 140 in y-direction. The displacement indicated by arrow 612 isan addition of the displacements 610 and 614. Additionally, adisplacement of the contact unit 150 relative to the substrate support130 is denoted by arrow 606. The individual areas of the test object arenumerated with roman numbers.

[0131] In FIG. 6, the contact unit covers several displays 301. The testobject consists in the present case exemplarily of six displays or ofthe areas I to XII, respectively. The six displays within the testobject are electrically connected with each other. Thereby, signals canbe sent to all displays via the contact unit or can be received from alldisplays, respectively.

[0132] The test range 302 of the electron beam measurement systemextends only over a small part of the test object. The substrate lies onthe substrate holder 130. The substrate holder has the dimensions 602 inx-direction and 604 in y-direction. In order to be able to measure alldisplays on the substrate, the substrate holder 130 has a displacementrange in x-direction according to arrow 610. Thereby, a sufficientdisplacement range is given to move the area VI in the test range 302 ofa test apparatus. A displacement range in y-direction according to arrow614 approves for the measurement of the area IXX. The area XXIV of adisplay being within FIG. 6 most distant from the test range 302 can beinspected with the displacements 612.

[0133] The test method is based in this example as well on the principledescribed with respect to FIGS. 3a to 3 d. At first, the area I of thetest object is inspected. Afterwards, the glass substrate 140 as well asthe contact unit 150 is for example moved in x-direction. The amount ofthe displacement is chosen so that area II can be inspected. Thereupon,area II is inspected. Thereafter, a synchronous displacement of thecontact unit 150 and glass substrate 140 is conducted again. Thisprocedure is repeated until all areas II to XII are tested.

[0134] Then, the contact unit and the substrate are moved relative toeach other (see 606) in order to be able to contact the next test object(areas XIII to XXIV) with the contact unit 150. All areas are alsotested within the area of this test object. Thereby, the contact unit150 is displaced essentially parallel during a displacement of therespective areas to the test range 302.

[0135] The previous embodiments referred exemplarily to a test methodwith a beam of charged particles. Since these test methods are verysensitive, it is preferred not to move the test apparatus, that is thebeam source, the beam shaping, the beam deflection, and the signaldetection. Thereby, for example a misalignment due to vibrations can bereduced.

[0136] A further test method is described in FIG. 10, the alignmentsensitivity of which is less. Therefore, also the optical axis of thetest apparatus can be displaced in the following example. FIG. 10 showsa beam source in the form of a lamp 910 with a beam shaping optics 911.The parallel light beams are guided via a beam divider 912 in thedirection of the surface of the substrate 140. The test objects forexample in the form of displays are arranged on the substrate. The beamis reflected within the measurement head 914. Additionally, there is amodulator within the measurement head 914, which is capacitively coupledwith the display to be tested. The modulator varies its localtransmission characteristics depending on the capacitive coupling to theindividual pixels of the display. The light beam, which propagates alongthe optical axis 102, is influenced by the varied transmissioncharacteristics. The local variations of the light beam corresponding toan individual pixels are measured by having the light beam, which isreflected at the measurement head 914, passing through the beam dividerand being imaged on the detection camera 916 with the optical system917.

[0137] A further aspect of the present invention results, since for thetest method described with respect to FIG. 10 the optical axis 102 canbe moved relative to the substrate with relatively few complications.This aspect is described in the following considering the embodimentaccording to FIGS. 11a to 11 d. Thereby, an analogous inventive methodfor contacting and testing of displays is concerned. For the previouslydescribed embodiments, the holder 130 with the substrate 140 wasdisplaced. Since the holder has, as compared to other components, alarge surface, it is necessary to provide a large floor space for theentire system in order to move the holder. Thus, space can be saved ifthe optical axis of the test apparatus and thereby the measurement range302 is displaced instead of the holder with the substrate. For verysensitive measurement apparatuses, as for example electron beammeasurement apparatuses, this is only limitedly possible. For thisreason, this aspect of the present invention is described with respectto an embodiment with a light optical measurement system analogously toFIG. 10.

[0138] Within FIG. 11a, the sample support 130 with the glass substrate140 is shown. The sample support is quasi fixed during the testactivity. In FIG. 11a, a constellation is shown, whereby at first afirst area 303 of the display is tested. Therefore, amongst others, atest apparatus or the optical axis 102 thereof, respectively, ispositioned so that the test range 302, which is indicated gray, coversat least the first area 303 of the first display to be tested. For alight optical method, the entire test range can for example be testedwith the quasi-parallel photon beam. Thereby, the measurement apparatusdirectly above the display to be tested comprises an optical modulator,which reacts on the pixel characteristics of the display via acapacitive coupling. The optical modulator changes that transmissioncharacteristics for the parallel photon beams. Thus, an image of thephoton beam onto a camera results in measurement result that can beevaluated.

[0139] Additionally to the positioning of the measurement apparatus withthe test range 302, the contact unit 150 is also positioned. The contactunit serves amongst others for the capacitive coupling between thepixels of the display to be tested and the optical modulator of themeasurement head 914 of the test apparatus (see FIG. 10). The displaycan for example be supplied with signals by the contacting of thecontact unit, whereby a test of the first area of the first display 301to be tested can be conducted.

[0140] The test of the second area 304 of the first display 301 to betested is conducted by a relative positioning of the components as shownin FIG. 11b. Therefore, the optical axis of the test apparatus andthereby the test range 302 is displaced as indicated by the arrow 902 inFIG. 11a.

[0141] After the testing of the second area 304 of the first display tobe tested (see FIG. 11b), the contact unit 150 is displaced as indicatedby arrow 904. Further, the optical axis of the test apparatus isdisplaced according to arrow 906. Thereby, the positioning of thecomponents relative to each other, which is shown in FIG. 11c, isachieved. According to FIG. 11c, a first area 303 of a further displayto be tested is positioned within the test range of the test apparatus.After the test of this area, the optical axis of the test apparatus isdisplaced according to arrow 902 a. Since all displays 301 are identicalwithin the present embodiment, the amount and the direction of thedisplacement 902 a corresponds to the displacement 902 (see FIG. 11a).

[0142] After the displacement 902 of the test apparatus and thus thetest range 302, the positioning of the components relative to each otheras shown in FIG. 11d is given. Thereby, the second area 304 of thefurther display to be tested lies within the test range 302 (markedgray) of the test apparatus. The second area of the further display cannow be tested.

[0143] All displays or all areas of all displays, respectively, can betested by further displacements of the contact unit and the optical axisof the test apparatus relative to the holder 130 or the glass substrate140, respectively.

[0144] According to the embodiments described with respect to thepresent invention, a large flexibility is given which makes an exchangeof contact units unnecessary. Furthermore, the displays increasing insize can be contacted by means of simply realized contact units, sincethe contact unit can follow the displacement of the test objects and theoptical axis of the corpuscular beam apparatus relative to each other.

[0145] While the foregoing is directed to embodiments of the presentinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. Method for positioning of a substrate and for contacting of a testobject with the following steps: a) putting the substrate with at leastone test object on a holder; b) positioning the substrate relative to anoptical axis of a test apparatus with a positioning activity; c)positioning the contact unit relative to the optical axis, whereby thecontact unit is positioned independent of the positioning activity ofthe substrate; d) contacting of at least one contact assembly of thetest object with the contact unit.
 2. Method according to claim 1,whereby during contacting of the contact unit with the at least onecontact assembly of the test object at least two contact pins of thecontact unit are contacted with contact pads of the at least one contactassembly, and whereby for contacting the contact pins of the contactunit are not moved relative to each other.
 3. Method according to any ofthe preceding claims, whereby the contact unit is positioned with an owndrive.
 4. Method according to any of the preceding claims, whereby thepositioning steps (b, c, respectively) comprise a movement perpendicularto the optical axis of at least 5 cm, preferably of at least 20 cm. 5.Method according to any of the preceding claims, whereby the steps b) tod) are repeated several times during testing of a substrate, preferablyat least between the testing of each test object.
 6. Method for testingof a substrate with several test objects with a test apparatus,comprising the following steps: putting the substrate on a holder;contacting of a first test object with a contact unit; positioning ofthe substrate so that a first area of the first test object lies in atest range of the test apparatus; testing of the first area of the testobject; displacing the substrate so that at least a further area of thefirst test object lies in the test range of the test apparatus;displacing the contact unit so that the position of the contact unit isessentially unchanged with respect to the first test object; testing ofthe further area of the test object; displacing the contact unit and thesubstrate relative to each other so that a further test object can becontacted.
 7. Method according to claim 6, whereby the contact unit isdisplaced by tracking.
 8. Method according to claim 6, whereby thecontact unit is displaced by carrying along.
 9. Method according to anyof claim 6 to 8, whereby the contact unit is displaced as long as acontact to the substrate is present.
 10. Method according to any ofclaim 6 to 9, whereby the test range is scanned by a beam deflection ofa corpuscular beam in two directions.
 11. Method according to any ofclaim 6 to 9, whereby the test range is scanned by a beam deflection ofa corpuscular beam in one direction and a substrate movement in anotherdirection.
 12. Method according to any of claim 6 to 11, whereby thecontact unit is displaced as long as no contact to the substrate ispresent.
 13. Method according to any of claim 6 to 12, whereby thecontact unit is adapted to different forms of test objects.
 14. Methodaccording to any of claim 6 to 13, whereby the testing is conducted byscanning of the test range with a corpuscular beam and measurement ofthe second area electrons.
 15. Method according to any of claim 6 to 14,whereby the testing is conducted by scanning of the test range with acorpuscular beam and measurement of a signal fed through the contactunit.
 16. Method according to any of claim 6 to 15, whereby before thetesting a vacuum of smaller than 1*10⁻³ mbar is generated.
 17. Apparatusfor contacting for the test of at least one test object (301) on asubstrate (140), comprising: a holder (130) for the substrate;displacement unit (132, 134) for the holder with a holder displacementrange in x-direction and a holder displacement range in y-direction; acontact unit (150) for contacting of the at least one test object,whereby the contact unit is displaceable in x-direction and iny-direction, and the contact unit displacement range in x-directionand/or the contact unit displacement range in y-direction are smallerthan the respective holder displacement range.
 18. Apparatus accordingto claim 17, whereby the contact unit displacement range in x-directionand in y-direction is larger than a corresponding contact alignmentdisplacement range (220, 222) of the contact unit.
 19. Apparatus forcontacting for the test of at least one test object (301) on thesubstrate, whereby for the test a test apparatus with an optical axis(102) is used, comprising: a holder (130) for a substrate with at leastone test object; a displacing unit for the holder; a contact unit (150)for contacting of the at least one test object, whereby the contact unitis displaceable and has essentially maximal the dimension of half of theholder dimension in one direction perpendicular to the optical axis. 20.Apparatus according to 19, whereby the contact unit has essentiallymaximal the dimensions of half of the holder the dimensions in twodirections perpendicular to the optical axis.
 21. Apparatus forcontacting for the test of at least one test object with a substrate(140), whereby for the test a test apparatus with an optical axis (102)is used, comprising: a holder (130) for the substrate displaceable withrespect to the optical axis (102); a displaceable contact unit (150),whereby the contact unit is displaceable during the test of thesubstrate with respect to the optical axis and with respect to theholder.
 22. Apparatus according to any of claim 17 to 21, whereby thecontact unit is displaceable by at least 5 cm, preferably by at least 20cm.
 23. Apparatus according to any of claim 17 to 22, whereby thecontact unit has dimensions, so that no area to be tested of the testobject to be tested is covered by the contact unit.
 24. Apparatusaccording to any of claim 17 to 23, whereby the contact unit has a sizewhich is larger than the test range (302) during testing.
 25. Apparatusaccording to any of claim 17 to 24, whereby the contact unit isconnected with a displacing unit with a drive (152) for displacementrelative to the optical axis.
 26. Apparatus according to any of claim 17to 25, whereby a synchronization unit (160) exists, which synchronizesthe displacing unit of the contact unit and of the holder.
 27. Apparatusaccording to any of claim 17 to 26, whereby the contact unit has contactpins for contacting.
 28. Apparatus according to claim 27, whereby thecontact pins for contacting with the contact unit (150) are not movablerelative to each other during the testing of a substrate.
 29. Apparatusaccording to claim 27, whereby the contact pins for contacting with thecontact unit (150) are not movable relative to each other.
 30. Apparatusaccording to any of claim 17 to 29, whereby the contact unit (150) isadjustable on different sizes of test objects.
 31. Apparatus accordingto any of claim 17 to 30, whereby the test object is at least onedisplay (301) with a contact assembly (200).
 32. Apparatus according toany of claim 17 to 31, whereby the apparatus is adapted to be used in avacuum.
 33. Apparatus according to any of claim 17 to 32, whereby thecontact unit is connected with an external control (162) and/or ameasurement unit (162).
 34. Apparatus according to any of claim 17 to32, whereby the contact unit is displaceable during the testing of thesubstrate.
 35. Test system comprising: an evacuable test chamber (108);a corpuscular beam column (104) with an optical axis (102); and anapparatus according to any of claim 17 to
 34. 36. Method for testing ofa substrate with several test object, whereby for testing a testapparatus with an optical axis is used, comprising the following steps:putting the substrate a holder; contacting of a first test object with acontact unit; positioning of the substrate and the optical axis relativeto each other so that a first area of the first test object lies in atest range of the test apparatus. testing of the first area of the testobject; displacing the substrate and the optical axis relative to eachother so that at least a further area of the first test object lies inthe test range of the test apparatus; testing of the further area of thetest object; displacing the contact unit and the substrate relative toeach other, so that a further test object can be contacted.
 37. Methodaccording to claim 36, whereby the optical axis of the test apparatus ispositioned relative to the substrate and the contact unit is displacedrelative to substrate.
 38. Method according to any of claim 36 to 37,whereby the test range is detected with a light optical system. 39.Method according to any of claim 36 to 38, whereby the contact unit isadapted to different forms of the test objects.
 40. Apparatus forcontacting for the test of at least one test object (301) on thesubstrate, whereby for the test a test apparatus with an optical axis isused, comprising: a holder (130) for substrate with at least one testobject; a displacing unit for displacement of the optical axis (102); acontact unit (50) for contacting of the at least one test object,whereby the contact unit is displaceable relative to the optical axisand independent thereof relative to the holder and has essentiallymaximal the dimension of a half of the holder dimension in one directionperpendicular to an optical axis.
 41. Apparatus according to claim 40,whereby the contact unit has essentially maximal the dimension of halfof the holder dimension in two directions perpendicular to an opticalaxis.
 42. Apparatus for contacting for the test of at least one testobject on the substrate (140), whereby for the test a test apparatuswith an optical axis (102) is used, comprising: an optical axis (102)displaceable with respect to the holder (130) for the substrate; adisplaceable contact unit (150), whereby the contact unit isdisplaceable during the testing of the substrate with respect to theoptical axis and with respect to the holder.
 43. Apparatus according toany of claims 40 to 42, whereby the contact unit is displaceable by atleast 50 mm, preferably by at least 200 mm.
 44. Apparatus according toany of claims 40 to 43, whereby the contact unit has dimensions so thatno area to be tested of the test object is covered by the contact unit.45. Apparatus according to any of claims 40 to 44, whereby the contactunit has a size larger than the test range (302) during testing. 46.Apparatus according to any of claims 40 to 45, whereby the contact unitis connected with a displacing unit with a drive (152) for displacementrelative to the optical axis.
 47. Apparatus according to any of claims40 to 46, whereby a synchronizing unit (160) exists, which synchronizesthe displacing unit of the contact unit and a further displacing unit.48. Apparatus according to claim 47, whereby the further displacing unitis a displacing unit for the optical axis.
 49. Apparatus according toany of claims 40 to 48, whereby the contact unit has contact pins forcontacting.
 50. Apparatus according to any of claims 40 to 49, wherebythe contact unit (150) is adaptable to different sizes of test objects.51. Apparatus according to any of claims 40 to 50, whereby the testobject is at least one display (301) with a contact arrangement (200).52. Apparatus according to any of claims 40 to 51, whereby the contactunit is connected with an external control (162) and/or a measurementunit (162).